Objective: To observe the clinical efficacy of “Qufeng Xingxue Tongluo Formula” in treating ischemic stroke and to explore its effect on platelet function. Methods Eighty cases with ischemic stroke were randomized into two groups:control group in which 40 cases were treated with conventional western medicine, and treatment group in which 40 cases were treated with “Qufeng Xingxue Tongluo Formula” additionally, with the course of 2 weeks. The degrees of neurologic impairment, spasm of limbs, motor function of limbs and changes of blood platelet parameters were observed.  Results: ① After treatment, scores of Ashworth and NIHSS were decreased in both groups (P<0.05), and FMI score was increased (P<0.05); scores of Ashworth and NIHSS in the observation group were lower than those of the control group (P<0.05), while the FMI score in observation group was higher than that of the control group (P<0.05); ② After treatment, the levels of thromboxane, homocysteine and von Willebrand factor were reduced in both groups (P<0.05), while the 6-keto - prostaglandin level was increased (P<0.05); the levels of thromboxane, homocysteine and von Willebrand factor of the observation group were lower than those of the control group (P<0.05), and the 6-keto - prostaglandin level of the observation group was higher than that of the control group (P<0.05); ③ After treatment, the platelet aggregation rate and the mean platelet volume (MPV) decreased in both groups (P<0.05), and the indicators of the observation group were lower than those of the controls (P<0.05).  Conclusion: “Qufeng Xingxue Tongluo Formula” is effective to improve the clinical symptoms and neurologic impairment in patients with ischemic stroke. Its mechanism may be association with improving the function of blood platelets and inhibiting the thrombosis.